1. Field of the Invention
The invention relates to a radial oscillating motor having a stator in a housing, a stator wing being disposed in the housing. A rotor having a driven shaft is supported in the housing and associated therewith is an identical number of rotor wings. The stator wing and the rotor wing in conjunction with the housing, the cylinder portion of the drive shaft and the two covers form a pressure chamber and one discharge chamber, which are sealed towards the inside by a frame sealing element which is inserted in the stator wing and the rotor wing, and which are sealed towards the outside and the inside by an annular sealing element. Further, a bearing, which has a pressure relief, is disposed in each cover of the stator between two sealing locations.
Such oscillating motors are used in particular in the aircraft and vehicle industry.
2. Description of the Related Art
DE 32 22 982 A1 describes a radial oscillating motor consisting of, for example, a housing, which has inside at least one stator wing and is closed off at the ends with covers, and a rotor which includes a driven shaft supported in the covers and at least one rotor wing. The rotor wing can oscillate within certain limits inside a free space in the housing and forms with the stator wing of the housing at least one pressure chamber and one discharge chamber. To ensure the internal leak-tightness between the pressure chamber and the discharge chamber, the stator wing and the rotor wing are provided with a form-fitting sliding sealing element which seals against the lateral covers and the radial housing wall and the driven shaft, respectively. To ensure external leak-tightness between the rotor and each cover, a sliding sealing ring which can be supported in the respective cover as well as in the rotor, is typically mounted on the driven shaft.
A number of other embodiments and modifications are possible.
The driven shaft is secured on the side of the journal by an additional sealing ring which can be fabricated from different rotary shaft seals.
Bearings are arranged on both sides of the driven shaft between the shaft seals, with overflow oil lines arranged in the region of the bearings for returning to the tank the leaked oil accumulating between the shaft seals. This arrangement not only protects the bearings and the sealing elements from an excessive pressure load, but also prevents damage to the bearings and the sealing elements and eliminates an excessive initial torque on the oscillating motor. The overflow oil lines are also provided with devices which maintain the leaked oil flow at a predetermined pressure, so that sufficient hydraulic oil is supplied to the bearings for lubrication.
Overflow lines of this type are technically required, but are implemented only reluctantly since technically complex devices and facilities are required which add to the cost. Moreover, a great number of pipes are required which significantly limits the application of the oscillating motors because of the limitations imposed by the mounting conditions.
In certain applications, it is disadvantageous to remove the overflow oil from the oscillating motor, for example, when the control system for the oscillating motor is malfunctioning and the rotor has to be kept in a fixed position. Leakage typically causes the rotor to yield to an externally applied load which may pose a safety risk.
It is therefore the object of the invention to develop a radial oscillating motor of the aforedescribed type without overflow oil lines and with bearings which operate at a reduced pressure while still receiving a sufficient quantity of lubricating oil.